It is useful to be able to use vehicles such as bulldozers with earth moving blades for hauling logs and felled trees through bush area while being able to protect the log gripping device against damage when the blade is being used for movement of earth. It is also desirable for environmental reasons that such vehicles be capable of being used without equipment projecting beyond the ends of the blade.
U.S. Pat. No. 4,645,410 to Royer discloses a device which is attached to the earth moving blade of a vehicle for use in hauling felled trees and logs. This device is attached to an end of the blade and permanently extends beyond the end of the blade. As a result the device is subject to damage when using the blade in a normal manner unless the device is first dismounted.
U.S. Pat. No. 4,781,518 to Paavila discloses a tree gripping device which is mounted on a bulldozer blade and permanently projects beyond the edge of the blade. Accordingly, this device is also subject to damage when using the bulldozer blade in the normal manner, unless the device is first dismounted.
The Royer and Paavila devices would also tend to cause environmental damage during use of the vehicle with the gripping devices not in use, by reason of the fact that the devices permanently project beyond the ends of the blades.